Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2009.3906.3911KatkhudaH. ShataratN. QablanH. 122009921An iterative least square time domain system identification method is developed in this study to identify the stiffness of each member and detect damages in plane frames with different support conditions, i.e., fixed, hinged and semi-rigid. The frames are represented by two dimensional beam finite elements, while the semi-rigid supports are modeled by using rotational springs. The stiffness of the elements are identified using theoretical dynamic response measurements only. The time history of the dynamic excitation force is not required in the identification process and the developed method has no restriction on types of forces to be used to excite the plane frames. The procedure detects damages by tracking the changes in stiffness of each element. With the help of several numerical examples, it is shown that the method can identify the structures very accurately and can detect damages in members of plane steel frames with different support conditions. It is shown that the procedure has the potential to be used as a nondestructive health assessment technique. The accuracy of the method is much better than other currently available methods in the literature.]]>Alampalli, S. and G. Fu,1997123237245Beck, J. and K. Yuen,2004130192203Barroso, L. and R. Rodriguez,2004130142151Housner, G.W., L.A. Bergman, T.K. Caughey, A.G. Chassiakos, R.O. Claus and S.F. Masri et al.,199713897971Koh, C., K. Tee and S. Quek,200613220182026Lam, H.F., S. Katafygiotis and N.C. Mickleborough,20041303448Law, S.S., Y.Z. Shi and L.M. Zhang, 199812412801288Ling, X. and H. Haldar,2004130877885Shi, Z.Y., S.S. Law and L.M. Zhang,2002128521529Ta, M., J. Lardies and B. Marc,200613429444Vestroni, F. and D. Capecchi,2000126761768Yuen, K.V., S.K. Au and J. Beck, 20041301633Yuen, K. and J. Beck,2003129920Wang, D. and A. Haldar, 1994120159176